Consin



Patented June 11, 1929.

UNITED STATES. PATENT OFFICE.

ARLIE SCHORGER, OF MADISON,

CONSIN.

WISCONSIN, ASSIGNOR, BY MESNE ASSIGNMENTS,

T0 BURGESS BATTERY (30., OF MADISON, WISCONSIN, A CORPORATION OF WIS-'No Drawing.

This invention relates to an improvement in plastic conductivecompositions.

It is the object of this invention to prov de a plastic conductivecomposition whichhas properties that make it superior for dry cellpurposes over those' compositions heretofore used.

In the manufacture of dry cells, and es- -pecially fiat dry cells, itusually becomes necessary to provide a plastic conductive mixture whichis used to cover a fiat metal base which acts as a conductivereenforcing member and prevents distortion of the plastic composition.In other types of cells the 'lcase may be in the form of a. rod, cup, or

other peculiar shape, as may be called for in the cell design. Thisplastic conductive mixture, which usually contains carbon or graphite asthe conductive-agent, also forms the cathode of the cell. If the drycell is of the Leclanch. type,-the plastic composition is the cathodeand must protect the metal base from the destructive action of the salaminoniac and 'zinc chloride which constitute.

the dry cell electrolyte. The plastic conductive composition mustnecessarily have a low resistance, necessitating athin coating over themetal base and also a high percentage of graphite or carbon.

- Heretofore graphite filled plastic conductive compositions havecontained various percentages of oils, rosin, varnishes, beeswax,parafiin, alone or in various combinations. A typical compositioncontains rosin, paraflin, and linseed oil. This mixture is soft whenheated so or it maybe appliedto a metal. base, such as sheet zinc. Whencold the mixture does not flow. Such a composition, when used in contactwith a dry cell depolarizing mix containing sal ammoniac or zincchlothat it may be hot rolled into sheets or rods,.

PLASTIC CONDUCTIVE COMPOSITION.

Application filed August 12, 1927. Serial No. 212,612.

ride, has several defects which I have over come by substituting.commercial Montan wax for the paraffin.

Montan wax is a true wax obtained from the brown coals of Germany. Ihave found that the Montan wax gives a better amalgamation with the restof the ingredients, raises the softening point, and gives a ermechanical resistance to penetration by the depolarizing mix.Furthermore the resulting plastic conductive composition shows a highresistance to the penetrative action of the depolarizing mix especiallyduring the warm summer weather. A plastic conductive compositioncontaining Montan wax in place of the paraffin shows little or nopitting when in contact with the depolarizing mix and as a' result amuch thinner coat may be used.

My preferred composition follows: rosin, 30 percent; raw linseed oil, 5percent; Montan wax, 5 percent; powdered graphite, percent. The graphiteconsists of equal parts of graphite passing a 200 mesh screen and grarosin, 0i and wax are melted together by heat to form a liquid afterwhich the graphite is stirred in while still hot until a'homogeneousplastic mass is formed. The comhite passing a 20 mesh screen. The

tougher composition. This results in a greatposit-ion is then rolled outor applied to the

